/**
 *  Copyright (c) 1997-2013, www.tinygroup.org (luo_guo@icloud.com).
 *
 *  Licensed under the GPL, Version 3.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.gnu.org/licenses/gpl.html
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.tinygroup.jspengine.el.lang;

import javax.el.FunctionMapper;
import java.lang.reflect.Method;

/**
 * @author Jacob Hookom [jacob@hookom.net]
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: tcfujii $
 */
public class FunctionMapperFactory extends FunctionMapper {

    protected FunctionMapperImpl memento = null;
    protected FunctionMapper target;
    
    public FunctionMapperFactory(FunctionMapper mapper) {
        if (mapper == null) {
            throw new NullPointerException("FunctionMapper target cannot be null");
        }
        this.target = mapper;
    }
   
    
    /* (non-Javadoc)
     * @see javax.el.FunctionMapper#resolveFunction(java.lang.String, java.lang.String)
     */
    public Method resolveFunction(String prefix, String localName) {
        if (this.memento == null) {
            this.memento = new FunctionMapperImpl();
        }
        Method m = this.target.resolveFunction(prefix, localName);
        if (m != null) {
            this.memento.addFunction(prefix, localName, m);
        }
        return m;
    }
    
    public FunctionMapper create() {
        return this.memento;
    }

}
